Method and apparatus for burning clayware



s sheets-sheet 1 RNEYS.

Filed Sept. 16

W. D RICHARDSON METHOD AND APPARATUS FOR BURNING CLAYWARE WlLLAED DRmH/Aensom INVENTOR.

Sept. 14 1926.

Sept. 14 1926. M5995@ w. D. RICHARDSON METHOD AND APPARATUS FOR BURNING CLAYWARE Filed sept. 16,'1924 s sheets-sheet 2 ng., Eg.

WILL/ARD D. RICHARDSON m/VENToR.v

l ATTORNEYS.

Septl 14 1926. 1,599,589

W. D. RICHARDSON METHOD AND APPARATUS FOR BURNING CLAYWARE I Fil'ed sept. 1e, 1924 :s sheets-sheets M v y l d ////ll l u 19 ,'J 'I v/ WILLAKD D. RICHARDSON INVENToR.

A TToR/EYS.

Patented Sept. 14, 1926.

uNrruDl STATES ...PATENT n nnrcnnnnson, or coLuMBus, onro.

METHOD AND APPARATUS FOR BURNING CLARE.

Application filed September 16, 1924. Serial No. 738,090.

. over and through the top and sides of the titi tunnel in the space between the ware on the cars and the crown and sides of the tunnel. Due to this longitudinal draft hitherto produced in these continuous tunnell kilns, the combustion gases, after passing the firing zone, come in contact with the ware in the water-smoking zone with the result that the sulphurous gases of combustion are condensed by the moisture from the'ware .at low temperatures forming sulphuric acid which acts upon certain bases inthe clay, changing them to soluble sulphates, which produce scumming and discoloration of the ware and has also been the cause of much damage to glazes. Furthermore, in burning clay'warein this type of tunnel kiln, the ware on the outer end top parts of the setting is burned to a different degree than the ware on the interior of the setting, with the result that a large amount of the burned ware is defective either from overburning in the top and outer portions of the setting or from underburning in the central bottom portion. t

My invention has to do primarily with the method of passing the hot gases of'combustion in contact with the ware only in the firing zone lsection of the continuous tunnel kiln and of preheating the air for combustion by radiation in the cooling zone of the tunnel and of preheating the ware in the preheating zone by radiation from the products of combustion in the firing zone. This method of burning `ware in a continuous tunnel kiln results in an even degree of burning of the ware by the hot gases of combustion in the ring zone and prevents scumming, discoloration or other damage to the Ware in the water-smoking and oxidation zones of the kiln. This novel method of burning clay ware is accomplished by the provision of a continuous tunnel kiln having specially constructed furnaces and draft outlets in the firing zone for produclng a positive cross draft of the hot gaseous products of combustion through the lower part of the car of ware bein burned in combination with suitable conduits in, or adjacent, the walls of the tunnel in both the preheated zone and cooling zone.

One of the objects of my invention is the provision of a tunnel kiln which is continnous and which is provided with a firingzone having furnaces alternately positioned on either side thereof and exhaust draft 'outlets positioned in the walls of the tunnel opposite such alternately positioned .furnaces. The result of this arrangement is that the hot gases of combustion from the furnaces will pass directly across the tunnel through flues in the car and the ware setting and into the draft outlets whereby the bottom portion of the ware on the cars is heated `to the desired temperature without overheating the ware at the top of the car setting.

Another object of my invention has to do with the provision in a tunnel kiln of a plurality of ware carrying 4cars for passing con tinuously through such tunnel and a blower at the discharge end of the tunnel for forcing air to be heated by the hot warein the cooling zone of the kiln'to the furnaces for combustion of the fuel; said blower to also force air to be heated by the hot ware in the cooling zone into the water-smoking and preheating zone for circulation therein.

Also an exhaust fan at the receiving end of the tunnel for the movement of the combustion gases through radiating pipes in the preheating zone but without any longitudinal draft through the tunnel from the firing zone.

' A further object of my invention contemplates the provision of a continuous tunnel kiln having preheating, tiring and cooling zones and passages in the walls of the tunnel extending to all three zones for controlling the distribution of gases and heat in such various zones. s Another object of my invention is the pro vision of a continuous tunnel kiln, a series of ware carrying cars adapted to pass substantially continuously through said tunnel kiln and a series of zones through which said ware carrying cars pass the cars in one zone being subjected to a radiating heat for preheating the ware; the ears in another zone mit lll@

bein subjected to hot combustion gases passing through the ware in adirection at right angles tothe movement of the cars; and the cars in another zone being subjected to a coolingaction whereby the heat radiated in the cooling process is utilized for preheating the air to be used for combustion andfor supplying hot air for circulation in the preheating zone.l

Various other features of my invention will be apparent as this description pro-` gresses and will be brought out in the claims appended hereto. The various ob jects of my invention may be obtained by the structure illustrated in the drawings, wherein similar characters of reference designate corresponding parts and wherein:

Figure l is a cross sectional plan view of a portion of my continuous tunnel kiln structure including the preheating and a portion of the firing zone and showing the manner of arranging the furnaces and draft outlets -in the ring zone and the manner of conducting the exhaust gases from the firing zone into the preheating zone.

Figure 2 is a cross sectional plan view similar to Figure l and showing the other end of my novel tunnel structure including aportion of the firing zone and the cooling zone and also illustrating the manner of utilizing the heat in the cooling portion of the continuous tunnel to preheat the air used for combustion.

Figure 3 is a vertical central longitudinal section of the structure shown in Figure l and showing the arrangement ofthe fur-` naces and draft outlets in the wall of the firing zone, the conduits for conducting pre' heated air to the furnaces and the products of combustion from the furnaces and the means for conducting the products of combustion from the tunnel without producing a longitudinal draft therein.

Figure 4 isa vertical c ntral longitudinal section of the structure siown in Figure 2 and showing in partcula the flues for conducting air through conduits in and adjacent the walls of the cooling Zone of the tunnel whereby the air is preheated prior to combustionvwithout causing a longitudinal draft in thecooling zone.

Figure 5 is a vertical cross section taken on line 5 5 of Figures l and 3 and showing a ware carrying car passing through the tunnel and conduits or radiating pipes arranged adjacent the walls in the preheating zone of the tunnel for prelieating the air by radiation.

Figure 6 is a vertical cross section taken on line 6-6 of Figures l and 3 and showing in detail the relative arran ement of the furnaces, cars and draft out ets in ithe ring zone. s

Figure 7 is a vertical cross section taken on line 7--7 of Figures 2 and 4 and illustrating the manner of conducting the preheated air from the cooling zone to the furnaces in the firing zone.

Figure 8 is a vertical cross section taken on line 8 8 of Figures 2 and 4 and showing the arrangement of conduits or pipes in the cooling zone of the tunnel forvpreheating and conducting the air to the furnaces and also showing the manner of arranging a space in the top of the tunnel7 for producing hot air available for drylng or waters'moking.

Figure 9 is a detail perspective view, partially cut away, of a portion of the'ring zone of my continuous tunnel kiln and showing the location and arrangement of the furnaces, draft outlets and flues for conducting the preheated air to and the products of `combustion from the ring zone.

In the drawings, and referring particularly to Figures 1 and 2, my tunnel kiln is shown as comprising a continuous tunnel, which, on account of its peculiarities of construction, ma be divided into three sections or zones. T ese zones may be calle'd the preheating zone, the firing zone, and the cooling zone and may be designated by the numerals 1, 2, and 3, respectively. The ware to be treated is passed through the tunnel and through the three zones by means of a series of cars 4 which are designed to be run upon suitable tracks 5 which extendthroughout the length of the tunnel. These cars may be of any desired design. ln the preferred form of m invention, I desire to provide each car wit a series of transverse supporting members 6 which are so spaced apart as to permit a free passage of gases between them and which are also so spaced as to provide a foundation for the ware upon the car. t

It will be understood that in this type of kiln the cars are moved slowly and continuously through the entire kiln and that as one car is moved into the preheating Zone of the kiln, another car is removed from the cooling end of the kilnf No particular mechanism is shown for advancing the cars through the tunnel and any type of mechanism may be utilized for this purpose. In

llU

Figure 3, l have shown a car 4 in position ready to be advanced towards the preheating zone proper of the tunnel kiln and ll have also shown a pusher rod'structure 7 which may be utilized in advancing the cars into and through the tunnel.

' As is best shown in Figures 5 to 9, the tunnel is provided with suitable troughs 8 which extend throughout the tunnel. These troughs are preferably filled with sand. Suitable Hanges 9 extending downwardly from each sideof the cars are designed to enter these sand troughs and thus provide a seal to revent the circulation of hot gases beneath t e car platform.

Iincasso rlhe vpreheating portion 1 of the tunnel is provided with a plurality of horizontal iues which are arranged vertically on each side of the tunnel and between the ware upon the cars and the walls of the tunnel. These flues may be designated l() and extend from a point adjacent the firing zone of the tunnel to suitable outlet conduits 11 at the entrance of the preheating zone. rl`hese outlet conduits 11 form the connecting means between an exhaust fan 12 and the lues 10. rllhese multiple dues 10 are preferably constructed of socketed refractory pipes of good conductive and radiative qualities in the hotter portion of the reheating zone, near the firing zone, and are constructed of cast iron pipes of the same cross section in the cooler portion of the reheating zone near the entrance or receiving end of the tunnel. These refractory dues and cast iron dues are continuous, with expansion joints in every unit of ipe. lin general, these llues 10 are designe to conduct all of the products of combustion from the bring zone to the exhaust fan 12 where they are exhausted to the atmosphere. Also, they conduct heat through their walls and radiate heat to the ware in the tunnel.

The central portion of my tunnel kiln, which may be designated the firing zone, is best illustrated in Figures 1, 6 and 9. 'lhis portion of the tunnel is provided with side walls which may preferably extend fairly close to the ware-upon the car and a crown 13 which is symmetrical with the crown which entends throughout the preheating zone. Fach wall-of the tunnel in the ring zone is provided with a series of alternately positioned furnaces 1d and draft outlets 15. Each furnace on one side of the firing zone wall is directly opposite the draft outlet on the opposite wall. Fach wall ofthe" tunnel in the firing zone is provided with draft collecting chambers 16 which chambers are connected to the draft dues 17 and have such connections regulable by means of suitable dampers 18 which may be, in turn, controlled by means of suitable handles, as best shownA in Figure 9, for controlling the effectiveness of the draft induced by the ex"- 'haust fan 12. rllhe air for combustion in the furnaces 11i is preheated in the cooling zone and conducted to the furnaces bymeans of suitable dues 19'located at the bottom walls of the firing zone of the tunnel. The

amount of air for combustion which is introduced into the furnaces 1d may be controlled by the dampers 20 which may be 'vta operated in a similar manner to the dempers 18. Although ll have shown the furnaces 14 as being provided with oil burners, it will be understood that any form of fuel may be utilized and combustion obtained by introducing the air through the dues 19. 'lhe air, for the combustion of the fuel in the furnaces 14 is conducted to the ilues or ducts 19 by means of suitable pipes or conduits 21 which extend along the side walls of the cooling portion of the tunnel, as best illustrated in Figures 4 and 8. The air is supplied to and forced through these pipes or conduits 21 by means of a suitable blower 22 positioned adjacent the discharge end of the tunnel. lt will be obvious that the air in passing through these pipes 21 will be heated by the heat stored in the cooling zone of the kiln and in the burnt ware.

The entrance end of the tunnel is provided with a suitable sealing means or door 23 and the discharge end of the tunnel is likewise provided with a suitable sealing means or door 24:.

ln the normal operation of my continuous tunnel kiln, the cars d are moved forwardly from left to right in Figures 1 to d, by the addition of each individual car or a series of cars at the entrance and the exit of a like number of cars at the discharge end of the tunnel. rlhus, all of the cars throughout the tunnel and in each zone will be simultaneously moved forward with the addition of each car in the preheating zone. The air for combustion may be drawn from the discharge end of the tunnel through the pipes 21 and dues 19 to the furnace, or may be forced through such pipes and dues by the blower 22, the air being preheated by the heat stored in the cooling zone ofthe kiln and in the burnt ware. 'lhis preheated air will pass along through the dues 19 and will be forced upwardly into the furnaces lll to combine with the oil or other fuel to produce combustion within such furnaces. rllhe exhaust fan 12 will ,then cause the hot gases of combustion in the furnaces to pass directly across the tunnel towards and through the draft outlets l5 and into the draft collecting chamberv 16. rlhe hot gases passing directly from the furnaces to the draft outlets will obviously pass between the ware supports 6 and through the ware in the bottom portion of the cars so as to heat such ware to the desired temperature without overheating the ware at the top of the car. Each furnace with its opposite draft Hue forms a'means of generating hot gases, and so the ware passes through a series of het gases while moving throu h the firing zone of the tunnel. lt will a so be obvious that the natural tendency of the hot gases ofY combustion is to rise toward the tot of the tunnel but this positive induced raft can be regulated by the dempers 18 so as to cause a sucient portion of the hot gases to pass directly and transversely between the furnaces 14 and the draft outlets 15. Controlled lby the size of the opening made by the dampers 18, the products of combustion will pass up into the draft flues 17'on either side of the furnace and then into the multiple series of pipes or llO irc y lconduits 10 which run along the side walls of the tunnel forming the preheating zone. In this zone the conduits l will abstract the Rheat from the gases by conduction and radiation and the ware upon the cars in the preheating zone will be initially heated by the radiation from such conduits and by connection of the hot air from the cooling zone.

Referring particularly to Figures 4 and 8 it will be seen that I have provided a chamber 25 in the crown of that portion of the tunnel designated the cooling zone. This chamber 25 extends from the discharge end of the tunnel to a point adjacent the firing zone. Cast iron plates 26 may serve to separate the chamber 25 from the main portion 3 of the cooling zone. this chamber 25 will be heated` by radiation of heat from the ware in the cooling zone. This heated air may`l then be conducted through suitable conduits 27 (see Figure 2) to the preheating zone 1. Thus the air in the preheating zone may be heated by radiation of heat from the products of combustion from the firing zone and also heated and dried directly by heated fresh air from the chamber 25. As the clay ware must be dry before entering the tunnel, some or all of this preheated air in the chamber may be conducted to a suitable drying or watersmoking kiln to dry and preheat the green Ware. A

It will be seen that I have provided a novel and very simple tunnel kiln for treating and burning clay ware without setting up longitudinal drafts from the firing zone in any part of the tunnel kiln. 1t will further be noted that Iv have provided a tunnel kiln 'which, while continuous, is divided into three zones, namely, a preheating zone, a firing zone, and a coolingr zone and which tunnel is so constructed that the ware in the preheating zone is not subjected to any longitudinal drafts from the ring zone or to sulphurous gases but which are merely preheated by radiation and convection. Furthermore, the tunnel adjacent the ring zone is so constructed that a suiiicient amount of the hot gases are passed directly and transversely across the lower portion of Athe tun'- nel and through the bottom portion of the ware upon the car. It will still further be seen that the air for combustion instead of Cil for the preheating of the fresh air to beA used in the preheating zone or water-smoking kiln may be constructed in such a manner that the chambers would extend down 05 `on each side of the tunnel or the chamber 25 Fresh air entering being preheated by passing directly over the as illustrated in Figures 4 and 8 may extend the entire length of the crown of the tunnelwhereby the fresh air may be preheated both in the cooling and firing zones and then conducted directly in the preheating zone. It will also be understood that the height of the arch over the furnace throat may be varied for diiferent products as may be further necessary to secure the uniform burning of the ware during the continuous movement of the cars through the firing zone.

It will be further understood that the preheating, firing, and cooling portions or zones of my tunnel kiln may be constructed of various lengths 'and sizes to accommodate various sizes of cars and Ware sections and various numbers of cars.

Having thus described my invention, what ll claim is:

1. The method of burning clay ware in tunnel' kilns which comprises subjecting the ware to a series of hot gases which-move in oplposite directions transversely of the tunne 2. The method of burning clay ware in tunnel kilns which consists in subjecting 4the ware on the conveying unit-s to hot gases which pass from furnaces in both walls of the tunnel, through the ware on the units and into draft Hues opposite said furnaces in opposite directions and at right angles to the direction of movement of the conveying units.

3. The method of burning clay ware in tunnel kilns containing preheating and .tiring zones, which consists in passing hot gases transversely through the ware setting in the ring zone and then utilizing these hot gases to heat'the air in the preheating zone by radiation. f

4. The method of burning clay ware in tunnel kilns containing preheating and firing compartments, which consists in passing the hot gases from one wall of the tunnel to the other wall in the firing zone and subjectingthe ware only in such firing zone to the direct contact of said hot gases.

5. The method of burning clay ware in tunnel kilns which comprises preheating the air for combustion by heat radiated from the ware, combining this preheated air with fuel, passing the hot gases transversely of the furnace to treat the ware and then preheating the 'Ware at the entrance of the tunnel by radi-ation from the products of combustion.

6. A car tunnel kiln comprising a firing zone for directing combustion gases upon and through the Ware and outlets provided only in such firing zone of the kiln for conducting the combustion gases therefrom.

7 A car tunnel kiln having a. ring zone- 8. A car tunnel kiln having single longitudinal lues in the outside Walls of the tun- ,nel in the firing or high-temperature zone,

and multiple longitudinal draft flues Within the tunnel in the preheating zone.

9. A car tunnel kiln comprising a firing zone, furnaces therein and recesses extending from the inner Wall of the tunnel `opposite each furnace in the firing zoneand ports or outlets from these recesses into a draftcollecting chamber.

l0. A car tunnel kiln having recesses in the inner Wall of the tunnel opposite each furnace in the firing zone, outlets from these recesses to a draft-collecting chamber, and dampered outlets from each of such chambers to a main longitudinal draft flue in each Wall of tunnel.

11. The method of burning clay Ware in tunnel kilns which comprises preheating air by Yradiation in the cooling zone and then conducting such preheated air directlyinto the preheating zone.

12. The method of burning clay Ware in tunnel kilns which comprises preheating both the air for combustion in the firing zone and air for drying in' the preheating zone by radiation in the cooling Zone. v

13. Tunnel kiln structure for burning clay Ware comprising means for heating the air for combustion by radiation, means for heating a separate chamber of air by radiation and means for conducting the preheated air to the firing zone and preheating zone.

14. A tunnel kiln comprising pre-heating, burning and cooling zones, said burning zone having alternate furnaces and draft lues arranged in each side, the furnaces in 40 each side being arranged substantially opposite the draft iues in the otherside. a

15. The method of burning clay Ware in tunnel kilns which consists in subjecting the Ware upon the conveying cars to hot gases from furnaces in the sides of the tunnel which pass through the Ware setting to draft lues opposite the respective furnaces.y

' 16. Tunnel kiln structure for burning clay Ware having a firing zone, furnaces arranged zone, and draft flues arranged `vopposite said furnaces. l

17.. The method of burningclay lWare tunnel kilns having prehea'ting, burning, and cooling zones, which comprises preheating air by radiation in the cooling zone, using such preheated air for combustion of fuel in the firing zone, passing the'products of .combustion through the ware setting transversely of the kiln, and then collecting suchproducts of combustion and utilizingthemfor heating the preheating zone by radiation.

18. The method of burning clay Ware in tunnel kilns which comprises heating they ware with hot gases which pass from furnaces on each side of the tunnel to oppositely disposed draft flues in opposite directions.v i

19." A tunnel kiln comprising preheating, burning andscooling zoneslfurnaces in said burning zone and draft lues opposite said furnaces in the firing zone and outlet ports fromthese draft flues communicatingvvith radiators 'in the preheating zone.

In testimony whereof I hereby affix 4my l signature.

Wir-.Liann D. RICHARDSON.

alternately in opposite Wall-s of said firing a 

